There are several places in the code that talk about removing accessible abandoned wiring. Other than under floor raceways they mostly refer to low voltage, computer and audio cables.You usually get away with leaving them if you tape them back and label them "spare" or words to that effect.

When drop ceilings are removed, there's what I call "sins of the past". Unsupported, fished, etc. LV cabling, and the occasional power wiring that more than likely was 'added' after the ceiling inspection(s)

We (NJ) enforce removals (LV), and whatever 'remains' has to be properly supported and identified. "Power wiring' is usually all removed, or re-installed.

I am talking about power cables, not LV. We do both commercial and residential remodel jobs. The last commercial job we did there was pipe and mc and a ceiling full of both disconnected and live circuits. We were told to just leave it up there.

We are getting ready to do a residential remodel job and I told the owner I am going to remove all the old disconnected MN-B I can get my hands on. (He can have it and take it to the recycle center.) I just donâ€™t like the idea of leaving all that old cable in the walls if I can easily rip it out.

OK, now for some commentary...In the NEC, references to abandonded wiring is within the LV Articles. (Period) There is no direct references to voltages, nor to wiring methods utilized within Article 300 wiring methods. Hence, we as EC's and AHJ's have to employ some common sense, which is also not referenced within the NEC.

Intent of removal is to reduce fuels in the event of a fire. Now, think about accidental powering of 'abandoned' conductors...possibly causing arcing, etc.

Additionally, there's the issue of having to work around all the 'junk' while doing you job. Also, explaining the stuff to the AHJ.

Owners that I have worked for as an EC have taken the position of complete removals, unless it is being reconnected. ALL LV is stripped out end to end.

Most of the Owners that I've run into want it all left "because it's cheaper and still meets the Code".I aks them if they have an issue if anything gets ripped out for free. Once they say that they don't care, the door's open for either creating a clear workspace or working around it...whichever way is easier for the Trades.

We don't have any electrical code rules in Canada but the fire protection act does. If the local jurisdiction uses the national fire code then abandoned wiring must be removed. Our local jurisdiction does not enforce it or the National fire code is not enacted here.

From a practical sense, the reason you want to remove unused cables is the hair ball you end up with if you don't. My wife's community is fixin to pay me $300 to remove all the unused computer cables from their server rooms and relabel the stuff that stays.If they had removed the stuff as they went along they wouldn't be in this pickle.I have seen so many old cables under a computer room floor it was blocking the air flow.